1. Field of the Invention
The present invention relates to fabrics against which a surface may be wiped to remove foreign particles, and in one aspect to such a cleaning fabric particularly adapted for the removal of foreign particles from photographic film.
2. Description of the Prior Art
U.S. Pat. No. 3,644,953 describes a device with which foreign particles can be removed from photographic film by passing the film between two lengths of cleaning fabric biased for intimate contact with the photographic film. An embodiment of this device is illustrated in FIG. 1 of the drawing. The device 10 illustrated therein includes a pair of support members or rollers 12 and 14 providing narrow support edges adapted for bringing narrow sections of two lengths 16 and 18 of cleaning fabric into intimate contact with the surfaces of a photographic film 20 passed therebetween. The support members 12 and 14 are spaced to afford slight compression of the lengths of cleaning fabric 16 and 18 as the photographic film 20 passes therebetween so that the support members 12 and 14 will provide intimate and complete contact between the lengths of cleaning fabric 16 and 18 and the photographic film 20.
After the photographic film 20 is cleaned by movement between the lengths of cleaning fabric 16 and 18, it passes adjacent a nuclear source of alpha particles 22 which neutralize charges on the cleaned film to restrict its attraction to dust particles in the air.
A mechanism is provided for changing the sections of the lengths of cleaning fabric 16 and 18 in the nip between the support members 12 and 14. This mechanism comprises a series of gears 24, 26, 28, 30, 32 and 34, driven by a motor 36 to wind the lengths of cleaning fabric 16 and 18 onto takeup spools 38 and off of supply spools 40.
Prior to the present invention the cleaning fabric used in the apparatus 10 for the accumulation of dust was a non-woven cloth of soft fine denier fibers bonded together at the fiber cross-over points by a resin binder. An example of such a cloth is that sold by the Pellon Corporation, Lowell, Mass., under the trade designation Grade 301W spun bonded polyamide web.
A cleaning fabric of this type can provide adequate cleaning for photographic film. However, the selection of the type or mixture of fibers used in cleaning fabrics of this type and of the method of bonding the fibers together requires a compromise between selecting fibers and a bonding system which provide a desirable resiliency in the cleaning fabric so that in use the fabric can be slightly compressed to insure even intimate contact by the cleaning fabric across the entire width of the photographic film while allowing the fabric to expand or be further compressed to compensate for irregularities in the film; and selecting fibers and a bonding system which provide a contact surface for the cleaning fabric which has few projecting fiber ends or fiber loops. Such projecting ends and loops, if they are present, tend to be cut or pulled from the lengths of cleaning fabric by the passage of a photographic film therebetween (i.e. as by the leading edge of a film, sprocket holes in the film, or a splice in the film), thereby providing a loose fiber which may become disposed on the surface of the photographic film. Such loose fibers can cause a serious blemish on a print of the film, and sometimes are left at the gate in automatic printing devices and cause blemishes on a series of subsequently produced prints.